According to their [Newton and his followers] doctrine, God Almighty wants to wind up his watch from time to time: otherwise it would cease to move. He had not, it seems, sufficient foresight to make it a perpetual motion. Nay, the machine of God's making, so imperfect, according to these gentlemen; that he is obliged to clean it now and then by an extraordinary concourse, and even to mend it, as clockmaker mends his work.

For FRICTION is inevitable because the Universe is FULL of God's works.For the PERPETUAL MOTION is in all works of Almighty GOD.For it is not so in the engines of man, which are made of dead materials, neither indeed can be.For the Moment of bodies, as it is used, is a false term—bless God ye Speakers on the Fifth of November.For Time and Weight are by their several estimates.For I bless GOD in the discovery of the LONGITUDE direct by the means of GLADWICK.For the motion of the PENDULUM is the longest in that it parries resistance.For the WEDDING GARMENTS of all men are prepared in the SUN against the day of acceptation.For the wedding Garments of all women are prepared in the MOON against the day of their purification.For CHASTITY is the key of knowledge as in Esdras, Sir Isaac Newton & now, God be praised, in me.For Newton nevertheless is more of error than of the truth, but I am of the WORD of GOD.

What is there about fire that's so lovely? ... It's perpetual motion; the thing man wanted to invent but never did. Or almost perpetual motion. ... What is fire? It's a mystery. Scientists give us gobbledegook about friction and molecules. But they don't really know.[Fahrenheit 451 refers to the temperature at which book paper burns. In the short novel of this title 'firemen' burn books forbidden by the totalitaran regime.]

[Ignorance] of the principle of conservation of energy ... does not prevent inventors without background from continually putting forward perpetual motion machines... Also, such persons undoubtedly have their exact counterparts in the fields of art, finance, education, and all other departments of human activity... persons who are unwilling to take the time and to make the effort required to find what the known facts are before they become the champions of unsupported opinionspeople who take sides first and look up facts afterward when the tendency to distort the facts to conform to the opinions has become well-nigh irresistible.

In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.
(1987) -- Carl Sagan